Dispensers for rolls of flexible sheet material, such as paper toweling, have been employed for a great many years. Dispensers are widely used in public lavatories to dispense paper toweling for users to dry their hands. Typically, a roll of sheet material is rotatably supported inside the dispenser cabinet. A user actuates a crank or lever that drives a feed mechanism for dispensing the sheet material. The feed mechanism typically includes a drive roller and an idle roller (or pinch roller). The crank or lever interacts with the drive roller so that actuation of the crank or lever rotates the drive roller. Rotation of the drive roller acts to unwind the sheet material roll. The crank or lever is usually a separate mechanism from the housing of the roll dispenser.
Recently, in order to provide more sanitary conditions and to improve the ease with which roll towel dispensers are used, “hands free” or “touchless” dispensers have been developed. Examples of such dispensers can be seen in U.S. Pat. Nos. 6,820,785, 6,745,927, and 5,772,291. These dispensers eliminate the manually operated crank or lever drive systems in favor of electrically operated drive systems that feed paper with minimal user effort.
In one form, hands free dispensers require a user to wave a hand (or other body part) in front of a sensor mounted in the front of the dispenser. In such constructions, a sensor is generally on or behind the dispenser's front cover. This approach makes the dispenser susceptible to accidental triggering and requires a user to first waive his or her wet hand, then move that or the other hand to the mouth of the dispenser to receive the paper as it's dispensed.
Another form of hands free dispenser starts with a length of paper extending from the dispenser. When the paper is tensioned or a length torn off, the dispenser automatically feeds another length. From a purely ergonomic point of view, this approach is more effective since a user need do nothing other than tear off the previously presented length of paper. However, this approach can be perceived as less sanitary since the length of paper extending from the dispenser prior to use is exposed to the environment for some period of time.
One of the problems with many conventional dispensers is that their configurations permit a user to cause the dispenser to “freewheel” or “free pull” such that an unlimited amount of paper can be pulled. Free pulling is made possible by the angular relationship between the dispenser mouth, the drive and idler roller and the cutting blade. More specifically, where the paper can be pulled in a straight line without contacting the cutting bar, free pulling is possible.
Another problem with conventional dispensers is that paper can jam in the mouth. This can be caused by one or more of a variety of factors including the weight of the paper, the curl of the paper, humidity, ragged edges and static electricity. In general, the narrower the mouth, the greater the likelihood of jamming. On the other hand, if the mouth is made too wide, the ability to free pull increases.
As a general rule, roll sheet material dispensers feed paper downwardly from the bottom of their housings through wide mouths. Some feed the paper straight down while others feed the paper somewhat outwardly as well as down. Depending on the height and placement of the dispenser, this feeding approach actually places the paper in a position that is less than optimal for a user to grasp it, particularly after waving a hand in front of the dispenser's housing. Moreover, the height and width of the mouth of most dispensers is such that when the paper is torn, the edge can get ragged resulting in paper jams and unsightly presentation. This is because there is very little, if any, limitation on the tearing angle that a user can employ to tear off a length of paper and because the size and shape of the mouth causes the ragged edge to catch and twist or fold up on itself. This may also be attributed to safety concerns that limit the sharpness of the blade that can be used. Because the size of the mouth of most dispensers is such that a user's fingers could fit within the housing and contact the blade, its sharpness must be limited.
Accordingly, a need exists for a sheet material dispenser that overcomes some or all of the disadvantages set forth above and provides an improvement over prior art dispensers.